Electrode arrangement



Filed Aug. 17, 1956 h 1N VENTOR.

WSMQ

United States Patent Ofice ELECTRODE ARRANGEMENT Franz Bronstert, Frankfurt am Main, Germany, assign'or to Accnmulatoren-Fabrik Aktiengesellschaft, Werk Hagen, Hagen, Westphalia, Germany Application August 17, 1956, Serial No. 604,755 Claims priority, application Germany August 18, 1955 6 Claims. (Cl. 2136- -43) I The present invention relates to an electrode arrangement, and more particularly to an-electrode arrangement for use in galvanic cells, storage batteries and the like.

- Galvanic elements, storage batteries and the like are known which include electrodes consisting of a plurality, of vertical electrode rods which are arranged spaced from each other and interconnected bypreferably horizontal electrically conductive connecting members. elements, batteries and the like, each of the vertical electrode rods is surrounded with active mass, and the active mass around each electrode rod is provided with a nonconductive tubular covering.

These tubular coverings of the active mass generally consist of hard rubber tubes or tubes of synthetic materials which are slitted at a right angle to the axis of the tube. These tubes are capable to a considerable degree to withstand the tendency of the active mass to expand. However, the non-slitted portions thereof are impermeable for the electrolyte, and the entire arrangement increases un-, favorably the inner resistance of the current. It has been attempted to overcome these disadvantages by providing tubular coverings of porous materials,. such as microporous hard rubber tubes, or mats or fabrics of glass, wool or synthetic fiber. However, these attempts did not succeed because the stability and firmness of the-porous tubes was insufiicient to restrain andv withstand the expansion of the active-mass in the course of operationof the device. It has also been attempted to form coverings for the active mass wihch comprise a porous tubular mem ber covered on its outer side by a perforated tube of synthetic material or hard rubber. Here again, the disadvantage of impermeable areas between the individual perforations of the outer tube was not overcomei It is therefore an object of the present invention to provide a coveringfor electrode rods and the active mass surrounding the same which overcomes the aforementioned disadvantages.

It is another object of the present invention to provide a covering for the active mass surrounding an electrode rod, which covering will withstand the tendency of the active mass to expand. I

i It is a further object of the present invention to provide a covering for the active mass surrounding an electrode rod of a galvanic cell, storage battery and 'the like, which covering will be highly permeable for the electrolyte and will withstand the tendency of the active mass to expand.

Other objects and advantages of the present invention will become apparent from a further reading of the description and the appended claims.

With the above and other objects in view, the present invention mainly comprises in a device of the character described, at least one body of active mass, an electrode rod embedded in the body of active mass, and an electrolyte-permeable covering about the body of active mass, the covering consisting essentially of glass fibers having a diameter of less than 10 n and having a chemical com position of between 68 and 72% SiO between 5 and In such Patented AugnA, 1959 3% A1 0 plus Fe O between 9 and 11% CaO, between 7 and 5% Na O, and between 11 and 9% K 0.

l The present invention also comprises in a device ofthe charatcer described, an electrode arrangement, comprising, in combination, a plurality of substantially vertical electrode rods spaced from each other, a plurality of substantially horizontal electrically conductive members interconnecting said spaced electrode rods, abody of active mass at least partially surrounding each of the electrode rods, respectively, and a tubular, electrolytepermeable covering about each of the bodies of active mass, respectively, the covering consisting essentially of glass fibers having a diameter of less than 10 and having alchemical composition of about 70% SiO about 4% A1 0 plus Fe O about 10% CaO, about 6% Na O, and about 10% K 0. V

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, willbe best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1' is an enlarged schematic view of a portion of z a glass fiber which may be used in the forming of an electrolyte-permeable covering according to the present invention;

Fig. 2 is an elevational view in cross-section of a covered electrode according to the present invention; j. Fig. 3 is a plane view in cross-section of a covered electrode according to the present invention; and

t .Fig. 4 is an elevational view partly in cross-section of a battery plate comprising a plurality of vertical electrode rodsspaced from each other and conductively inter-jc'onnected, each provided with a covering according to the present invention.

I Referring nowto the drawing, Fig. 1 shows a glass fiber 1 such as is employed in forming the fabric or mat of the electrode covering according 'to the present inven- 7 tion. The diameter of the glass fiber is equal to or less L than 10 preferably about 7 ,u.

As" illustrated in Figs. 2 and 3 of the drawing, a tubular covering 2 is formed of material such as glass fibers 1.. This highly porous, non-conductive tubular cov- 1 ering is arranged concentrically about an electrode rod 3 made of lead. The annular space 4 between the electrode rod 3 and'the tubular covering 2 is filled with active mass, such as PbO Fig. 4 illustrates an entire battery plate according to the present invention which comprises a plurality of substantially vertical electrode rods 5 which are spaced from each other and which are electrically conductively interconnected by conductive members 6 and ,7. Each individual electrode rod 5 is embedded in a body of active mass 9 about which is arranged the electrolyte-permeable covering 8. The battery plate is provided with a terminal 10.

The glass fibers of which according to the present invention the electrode covering is formed, consist of between 68 and 72% SiO between 5 and 3% A1 0,; and Fe O between 9 and 11% CaO, between 7 and 5% Na O, and between 11 and 9% K 0.

Surprisingly it has been found that the strength of glass fibers can be increased by employing glass fibers having a diameter of less than 10 ,u, to such an extent that mats or fabrics made of such glass fibers will withstand the pressure of the active mass. It has been found that by reducing the diameter of the glass fibers, the strength thereof increases beyond the strength even of high grade steel of similar dimensions. However, the concurrent increase in surface area of the glass fibers which is caused by reduction of the diameter thereof, makes the same vulnerable to chemical attack by the electrolyte and to oxidation by oxygen emanating in 'ftatu nascendi from the active mass.-

- According-to the present inventionithas; now been found that glass fibers. of very small diameter will be resistant against chemical attack by the electrolyte and against oxidation, if composed of between-68 and72 SiO between 5 and 3% A1 plus Fe O between 9 and 11% CaO, between 7 and 5% Na O, and between 11 and 9% K 0. Preferably the composition of the glass fibers is about 70% SiO aboutr4% A1 0 plus Fe O about l0% CaO, about 6% Na O, and about K 0, By using tubular coverings for the active mass consisting according to the present invention of glass fibers of one of the above compositions and having a diameter of less than 10 preferablyof about 7 an increase in the amount of current of 50% over the amount of current obtained with conventional slitted hard rubber coverings, was obtained. Upon continuous operation in storage batteries it w'asfound that the covering according to the present invention in spite of lesser thickness than conventional slitted hard rubber coverings, could withstand the pressure of the active mass during one thousand discharges of the battery without bulging or breaking, since the individual glass fibers were not weakened by chemical attack thereon. It will be understood that each of the elementsdescribed'above, or two or more together, may also a. useful application in other types'of electrode arrange ments differing from the types described above.

While the invention has been illustrated and described as embodied in an electrode covering, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing any way from the spirit of the present invention. Without further analysis, the foregoing will so fully reveal thegist of the present invention that others can by applying" current knowledge readily adapt it for vari: ous applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention 4 covering about each of said bodies of active mass, said covering consisting essentially of glass fibers having a diameter of less than 10 a and having a chemical composition of about 70% SiO about 4% of at least one substance selected from the group consisting of A1 0 and Fe O about 10% CaO, about 6% Na O, and about 10%K O.---- I p 3. In an electrode arrangement, an insulating, electrolyte-permeable electrode covering consisting essentially of glas fibers having a diameter of less than 10 a and having a chemical composition of'between 68 and 72% SiQ between 5 and 3% of at least one substance selected from the group consisting of A1 0 and Fe o and, therefore, such adaptations should and are intended equivalence of the following claims. a

, What is claimed as new and desired to be secured by Letters Patent is:

1 In an electrode arrangement, at least one body of active mass; an electrode rod embedded in said body of active mass; and an electrolyte-permeable, covering about said body of active mass, said covering consisting essentially of glass fibers having a diameter of less than 10 and having a chemical composition of between to be comprehended within the meaning and range of 68 and 72% SiO between 5 and 3% of at least one substance selected from the group consisting oi A l Q and Fe 0 between 9 and 11% CaO, between 7 and 5% Na O, and between 11 and 9% K 0.

2. In an electrode arrangement, a plurality of bodies of active mass; an electrode rod: embedded in each of said bodies of active mass; and an electrolyte-permeablev between 9 and 11% CaO, between 7'and 5% Na O, and between 11 and 9% K Q.

4. In an electrode arrangement, a plurality of bodies of active mass; an electrode rod embedded in each of said bodies of active mass; and an electrolyte-permeable covering about each ofsaid bodies of active mass, said covering consisting essentially of a glass fiber fabric, each of the glass fibers'thereof having a diameter-of less than 10 ,u and having a chemical composition of between 68, and 72% SiO ',-between 5 and 3% of at least one substance selected from the group consisting of A1 0 and Fe O between 9 and 11% CaO, between 7-and5% Na- O, and between 11 and 9% K 0.

5. In an electrode arrangement, in combination, a plurality of substantially vertical electrode rods spaced from each other; a plurality of substantially horizontal electrically conductive members interconnecting said spaced electrode rods; a body of active mass at least partially surrounding each of said electrode rods, respectively; and a tubular, electrolyte-permeable covering about each of said bodies of active mass, respectively, saidcovering consisting essentially of glass fibers having a diameter of less than 10 n and having a chemical composition ofbetween 68 and 72% SiO between 5 and 3% of at least one substance selectedtfrom the group consisting of A1 0 and Fe O between 9 and 11% CaO, between 7 and 5% Na O, and, between 11 and 9% K 0. 6. In an electrode arrangement, at least one body of active mass; an electrode rod embedded in said body of active mass; and an electrolyte-permeable covering about'said body of active mass, said covering consisting essentially of glass fibers having a diameter of about 7 ,u and'having a chemical composition of between 68 and 72% SiO between 5 and 3% of at least one substance selected from the group consisting of A1 0 and Fe O between 9 and 11% CaO, between 7 and 5% Na O, and between 11 and 9% K 0. 1

References Cited in the file of this patent UNITED STATES PATENTS 2,128,7(22 Gelstharp I Aug. 30, 1938 2,125,212 Ha Mar. 26, 1940 2,210, 5 ,d l k ,-t-,-.-'- A1181 4 2,343,970 Galloway Mar. 14, 19.44 -i-.'"',',.'-"""':"".--'f"-' June 3 3 28 W te. Apr- 10, 1945 

